U.S. patent application number 14/139963 was filed with the patent office on 2015-01-29 for display device and method of manufacturing the same.
This patent application is currently assigned to Samsung Display Co., Ltd.. The applicant listed for this patent is Samsung Display Co., Ltd.. Invention is credited to SEUNGHWAN CHUNG, JAEJOONG KWON, Hayoung LEE.
Application Number | 20150028739 14/139963 |
Document ID | / |
Family ID | 52389901 |
Filed Date | 2015-01-29 |
United States Patent
Application |
20150028739 |
Kind Code |
A1 |
KWON; JAEJOONG ; et
al. |
January 29, 2015 |
DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME
Abstract
A display device includes a base substrate, a plurality of
pixels disposed on the base substrate, a light collecting member
disposed on the plurality of pixels, and an encapsulation member
disposed on the light collecting member and facing the base
substrate to cover the plurality of pixels, where the light
collecting member includes a light collecting layer including a
protrusion pattern disposed on an upper surface of the light
collecting layer and the protrusion pattern is protruded in one
direction to change an optical path of a light passing through the
light collecting layer.
Inventors: |
KWON; JAEJOONG; (Suwon-si,
KR) ; LEE; Hayoung; (Seoul, KR) ; CHUNG;
SEUNGHWAN; (Asan-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., Ltd. |
Yongin-City |
|
KR |
|
|
Assignee: |
Samsung Display Co., Ltd.
Yongin-City
KR
|
Family ID: |
52389901 |
Appl. No.: |
14/139963 |
Filed: |
December 24, 2013 |
Current U.S.
Class: |
313/512 ;
445/25 |
Current CPC
Class: |
H01L 51/5271 20130101;
H01L 51/5262 20130101; H01L 51/5275 20130101; H01L 27/3244
20130101 |
Class at
Publication: |
313/512 ;
445/25 |
International
Class: |
H05B 33/12 20060101
H05B033/12; H05B 33/10 20060101 H05B033/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2013 |
KR |
10-2013-0088114 |
Claims
1. A display device comprising: a base substrate; a plurality of
pixels disposed on the base substrate; a light collecting member
disposed on the plurality of pixels; and an encapsulation member
disposed on the light collecting member and facing the base
substrate to cover the plurality of pixels, wherein the light
collecting member comprises a light collecting layer including a
protrusion pattern disposed on an upper surface thereof and the
protrusion pattern is protruded in one direction to change an
optical path of a light which passes therethrough.
2. The display device of claim 1, wherein the protrusion pattern
comprises a plurality of prism mountains.
3. The display device of claim 2, wherein the plurality of prism
mountains are extended in a direction substantially in parallel to
a surface of the base substrate.
4. The display device of claim 3, wherein each of the plurality of
prism mountains has a polygonal shape, a semi-circular shape, or a
semi-oval shape when viewed in a cross-sectional view perpendicular
to the surface of the base substrate and the direction.
5. The display device of claim 1, wherein the light collecting
member further comprises a planarization layer disposed on the
light collecting layer to cover the protrusion pattern.
6. The display device of claim 5, wherein the light collecting
layer has a refractive index different from a refractive index of
the planarization layer.
7. The display device of claim 6, wherein the refractive index of
the light collecting layer is greater than the refractive index of
the planarization layer.
8. The display device of claim 6, wherein the refractive index of
the light collecting layer is smaller than the refractive index of
the planarization layer.
9. The display device of claim 1, wherein the light collecting
layer is provided in a plural number, and protrusion patterns of
the light collecting layers are overlapped with each other when
viewed in a plan view.
10. The display device of claim 9, wherein the light collecting
layers comprise: a first light collecting layer disposed on the
plurality of pixels and having a first protrusion pattern; and a
second light collecting layer disposed on the first light
collecting layer and having a second protrusion pattern.
11. The display device of claim 10, wherein the first protrusion
pattern is extended in a first direction substantially in parallel
to a surface of the base substrate and the second protrusion
pattern is extended in a second direction substantially in parallel
to the surface of the base substrate and crossing the first
direction.
12. The display device of claim 11, wherein each of the plurality
of pixels comprises: a first electrode disposed on the base
substrate; a light emitting layer disposed on the first electrode;
and a second electrode facing the first electrode while interposing
the light emitting layer therebetween.
13. The display device of claim 1, further comprising a color
filter disposed between the light collecting member and the
encapsulation member.
14. A method of manufacturing a display device, comprising:
disposing a plurality of pixels on a base substrate; disposing a
light collecting member on the plurality of pixels; disposing an
encapsulation member on the light collecting member; and providing
a light collecting layer in the light collecting member, wherein
the light collecting layer includes a protrusion pattern disposed
on an upper surface thereof and the protrusion pattern is protruded
in one direction.
15. The method of claim 14, wherein the providing the light
collecting layer in the light collecting member comprises:
disposing a polymer resin layer on the plurality of pixels;
disposing a mold having a preliminary pattern on the polymer resin
layer; transferring the preliminary pattern to the polymer resin
layer, which provides the protrusion pattern on the polymer resin
layer; and curing the polymer resin layer.
16. The method of claim 15, wherein the disposing the light
collecting member on the plurality of pixels comprises disposing a
planarization layer on the light collecting layer.
17. The method of claim 16, wherein the light collecting layer has
a refractive index different from a refractive index of the
planarization layer.
18. The method of claim 17, wherein the light collecting layer is
provided in a plural number, and protrusion patterns of the light
collecting layers are overlapped with each other when viewed in a
plan view.
19. The method of claim 18, wherein the disposing the light
collecting member on the plurality of pixels further comprises:
disposing a first collecting layer having a first protrusion
pattern on the plurality of pixels; and disposing a second
collecting layer having a second protrusion pattern on the first
collecting layer.
20. The method of claim 19, wherein the first protrusion pattern is
extended in a first direction substantially in parallel to a
surface of the base substrate and the second protrusion pattern is
extended in a second direction substantially in parallel to the
surface of the base substrate and crossing the first direction.
Description
[0001] This application claims priority to Korean Patent
Application No. 10-2013-0088114, filed on Jul. 25, 2013, and all
the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of which are hereby incorporated by reference in their
entirety.
BACKGROUND
[0002] 1. Field
[0003] The invention relates to a display device and a method of
manufacturing the same. More particularly, the invention relates to
a display device having high front surface brightness and a method
of manufacturing the display device.
[0004] 2. Description of the Related Art
[0005] A flat panel display device is generally classified into a
light emission type and a light receiving type. As the light
emission type display device, a plasma display panel and an
electroluminescent display device, for example, are used. As the
light receiving type, a liquid crystal display device, for example,
is used. Among them, the electroluminescent display device has been
spotlighted as a next generation display device since it has
properties, such as fast response speed, low driving voltage, thin
thickness, etc., for example. The electroluminescent display device
is classified into an inorganic electroluminescent display device
and an organic electroluminescent display device depending on a
material used to form a light emitting layer.
[0006] The organic electroluminescent display device is a
self-emissive display device that electrically excites a
fluorescent organic compound to emit light. The organic
electroluminescent display device has been spotlighted as a next
generation display device since it has properties, such as fast
response speed, low driving voltage, thin thickness, etc., for
example, when compared to the liquid crystal display device.
[0007] The organic electroluminescent display device includes a
light emitting layer formed of an organic material and disposed
between an anode electrode and a cathode electrode. When positive
and negative voltages are respectively applied to the electrodes, a
hole is injected into the light emitting layer through a hole
transport layer and an electron is injected into the light emitting
layer through an electron transport layer. The holes and the
electrons are recombined in the light emitting layer to generate an
exciton. The light emitting layer emits light when an excited state
of the exciton changes to a ground state, thereby an image is
displayed.
SUMMARY
[0008] Exemplary embodiments of the invention provide a display
device including a base substrate, a plurality of pixels disposed
on the base substrate, a light collecting member disposed on the
plurality of pixels, and an encapsulation member disposed on the
light collecting member and facing the base substrate to cover the
plurality of pixels. The light collecting member includes a light
collecting layer including a protrusion pattern disposed on an
upper surface thereof and the protrusion pattern is protruded in
one direction to change an optical path of a light passing
therethrough.
[0009] In an exemplary embodiment, the protrusion pattern may
include a plurality of prism mountains and the plurality of prism
mountains are extended in a direction substantially in parallel to
a surface of the base substrate. In an exemplary embodiment, each
of the plurality of prism mountains may have a polygonal shape, a
semi-circular shape, or a semi-oval shape when viewed in a
cross-sectional view perpendicular to a surface of the base
substrate and the direction.
[0010] In an exemplary embodiment, the light collecting member may
further include a planarization layer disposed on the light
collecting layer to cover the protrusion pattern. In an exemplary
embodiment, the light collecting layer may have a refractive index
different from a refractive index of the planarization layer, and
the refractive index of the light collecting layer is greater than
the refractive index of the planarization layer.
[0011] Exemplary embodiments of the invention provide a method of
manufacturing a display device including disposing a plurality of
pixels on a base substrate, disposing a light collecting member on
the plurality of pixels, disposing an encapsulation member on the
light collecting member, and providing a light collecting layer in
the light collecting member where the light collecting layer
includes a protrusion pattern disposed on an upper surface thereof
and the protrusion pattern is protruded in one direction.
[0012] In an exemplary embodiment, the providing the light
collecting layer in the light collecting member may include
disposing a polymer resin layer on the plurality of pixels,
disposing a mold having a preliminary pattern on the polymer resin
layer, transferring the preliminary pattern to the polymer resin
layer, which provides the protrusion pattern on the polymer resin
layer, and curing the polymer resin layer.
[0013] According to the above, the front brightness of the display
device is enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other advantages of the invention will become
readily apparent by reference to the following detailed description
when considered in conjunction with the accompanying drawings, in
which:
[0015] FIG. 1 is an exploded perspective view showing an exemplary
embodiment of a display device according to the invention;
[0016] FIG. 2 is a circuit diagram showing one pixel;
[0017] FIG. 3 is a plan view showing a pixel shown in FIG. 1;
[0018] FIG. 4 is a cross-sectional view taken along line I-I' of
FIG. 3;
[0019] FIG. 5 is a perspective view showing an exemplary embodiment
of a light collecting member according to the invention;
[0020] FIGS. 6A to 6G are cross-sectional views showing an
exemplary embodiment of a method of manufacturing a display device
according to the invention;
[0021] FIGS. 7A and 7B are graphs showing an exemplary embodiment
of an intensity of light as a function of a viewing angle of a
conventional display device and a display device according to the
invention; and
[0022] FIGS. 8A to 8C are perspective views showing exemplary
embodiments of light collecting layers according to the
invention.
DETAILED DESCRIPTION
[0023] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which various
embodiments are shown. This invention may, however, be embodied in
many different forms, and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the scope of the invention to those skilled in
the art. Like reference numerals refer to like elements
throughout.
[0024] It will be understood that when an element or layer is
referred to as being "on", "connected to" or "coupled to" another
element or layer, it can be directly on, connected or coupled to
the other element or layer or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly connected to" or "directly coupled to"
another element or layer, there are no intervening elements or
layers present. Like numbers refer to like elements throughout. As
used herein, the term "and/or" includes any and all combinations of
one or more of the associated listed items.
[0025] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another region,
layer or section. Thus, a first element, component, region, layer
or section discussed below could be termed a second element,
component, region, layer or section without departing from the
teachings of the invention.
[0026] Spatially relative terms, such as "beneath", "below",
"lower", "above", "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
In an exemplary embodiment, when the device in the figures is
turned over, elements described as "below" or "beneath" other
elements or features would then be oriented "above" the other
elements or features. Thus, the exemplary term "below" can
encompass both an orientation of above and below. The device may be
otherwise oriented (rotated 90 degrees or at other orientations)
and the spatially relative descriptors used herein interpreted
accordingly.
[0027] The terminology used herein is for the purpose of describing
particular exemplary embodiments only and is not intended to be
limiting of the invention. As used herein, the singular forms, "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "includes" and/or "including", when used
in this specification, specify the presence of stated features,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0028] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0029] Exemplary embodiments are described herein with reference to
cross section illustrations that are schematic illustrations of
idealized embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, embodiments described
herein should not be construed as limited to the particular shapes
of regions as illustrated herein but are to include deviations in
shapes that result, for example, from manufacturing. For example, a
region illustrated or described as flat may, typically, have rough
and/or nonlinear features. Moreover, sharp angles that are
illustrated may be rounded. Thus, the regions illustrated in the
figures are schematic in nature and their shapes are not intended
to illustrate the precise shape of a region and are not intended to
limit the scope of the present claims.
[0030] Hereinafter, the invention will be explained in detail with
reference to the accompanying drawings.
[0031] FIG. 1 is an exploded perspective view showing a display
device according to an exemplary embodiment of the invention, FIG.
2 is a circuit diagram showing one pixel, FIG. 3 is a plan view
showing a pixel shown in FIG. 1, and FIG. 4 is a cross-sectional
view taken along line I-I' of FIG. 3.
[0032] Referring to FIGS. 1 to 4, the display device is an organic
light emitting display device including an organic light emitting
layer. In the exemplary embodiment, for the convenience of
explanation, a direction in which an image is displayed on the
display panel and at which a user is present will be referred to an
upward direction or a forward direction, and a direction opposite
to the upward direction will be referred to a downward direction or
a backward direction, but they should not be limited thereto or
thereby.
[0033] The display device includes a base substrate BS, pixels PXL,
a light collecting member LCM, a color filter CF, and an
encapsulation member ENC.
[0034] In an exemplary embodiment, the base substrate BS has a
rectangular plate shape with long sides and short sides. The pixels
PXL are arranged on the base substrate BS in a matrix form.
[0035] Referring to FIG. 2, the pixel PXL includes a line part
configured to include a gate line GL, a data line DL and a driving
voltage line DVL, a thin film transistor ("TFT") connected to the
line part, an organic light emitting device EL connected to the TFT
and a capacitor Cst.
[0036] The gate line GL is extended in one direction. The data line
DL is extended in another direction crossing the gate line GL. The
driving voltage line DVL is extended in a direction substantially
in parallel to the data line DL. The gate line GL applies a scan
signal to the TFT, the data line DL applies a data signal to the
TFT, and the driving voltage line DVL applies a driving voltage to
the TFT.
[0037] The TFT includes a driving TFT TR2 to control the organic
light emitting device EL and a switching TFT TR1 to switch the
driving TFT TR2. In the illustrated exemplary embodiment, one pixel
PXL includes two TFTs TR1 and TR2, but a number of the TFTs should
not be limited to two. That is, one pixel PXL may include one TFT
and one capacitor, or three or more TFTs and two or more
capacitors.
[0038] Referring to FIG. 3, the switching TFT TR1 includes a first
gate electrode GE1, a first source electrode SE1 and a first drain
electrode DEL The first gate electrode GE1 is connected to the gate
line GL and the first source electrode SE1 is connected to the data
line DL. The first drain electrode DE1 is connected to a gate
electrode (i.e., a second gate electrode GE2) of the driving TFT
TR2. The switching TFT TR1 transmits the data signal applied to the
data line DL to the driving TFT TR2 in response to the scan signal
applied to the gate line GL.
[0039] The driving TFT TR2 includes the second gate electrode GE2,
a second source electrode SE2 and a second drain electrode DE2. The
second gate electrode GE2 is connected to the switching TFT TR1,
the second source electrode SE2 is connected to the driving voltage
line DVL, and the second drain electrode DE2 is connected to the
organic light emitting device EL.
[0040] Referring to FIG. 4, the organic light emitting device EL
includes a light emitting layer EML, a first electrode EL1, and a
second electrode EL2 facing the first electrode EL1 while
interposing the light emitting layer EML between the first and
second electrodes EL1 and EL2. The first electrode EL1 is connected
to the second drain electrode DE2 of the driving TFT TR2. The
second electrode EL2 receives a common voltage, and the light
emitting layer EML emits a light in response to an output signal of
the driving TFT TR2 to display an image. In an exemplary
embodiment, the light emitted from the light emitting layer EML may
be a white light.
[0041] Referring to FIGS. 2 and 3, the capacitor Cst is connected
between the second gate electrode GE2 and the second source
electrode SE2 of the driving TFT TR2 and charged with the data
signal applied to the second gate electrode GE2 of the driving TFT
TR2 to maintain the data signal applied to the second gate
electrode GE2.
[0042] Referring to FIGS. 3 and 4, the light collecting member LCM
is disposed on the pixels PXL and collects the light exiting from
the pixels PXL in the upward direction. The light collecting member
LCM includes a transparent material. The light collecting member
LCM may include a light collecting layer on which a convex pattern
is provided to change an optical path of the light passing through
the light collecting layer. The light collecting layer LCM will be
described in detail later.
[0043] The color filters CF are provided to correspond to the
pixels PXL in a one-to-one correspondence to allow the pixels PXL
to represent colors. The color filters CF include color filters
displaying different colors from each other. In an exemplary
embodiment, the color filters CF include a red color filter, a
green color filter, and a blue color filter, which respectively
display red, green, and blue colors, for example. In an exemplary
embodiment, the color filters CF may further include color filters,
which display a cyan color, a magenta color, a yellow color, a
white color, etc.
[0044] In the illustrated exemplary embodiment, the white light
exits from the pixels PXL and is changed to a color light, but it
should not be limited thereto or thereby. In an exemplary
embodiment, different color lights may exit from the pixels PXL,
and thus the color filters CF may be omitted. In addition, the
white light may exits from a portion of the pixels PXL and the
color light may exit from the other portion of the pixels PXL. In
this case, the color filters CF may be omitted or not according to
the pixels PXL from which the white light or the color light
exits.
[0045] The encapsulation member ENC is disposed on the color
filters CF to seal the pixels PXL and the color filters CF.
[0046] Hereinafter, the display device according to the illustrated
exemplary embodiment of the invention will be described.
[0047] In the display device, the base substrate BS includes areas
in which the pixels PXL are disposed. The base substrate BS may
include an insulating material, such as glass, plastic, and
crystal.
[0048] A buffer layer BFL is disposed on the base substrate BS. The
buffer layer BFL prevents impurities from being diffused into the
switching TFT TR1 and the driving TFT TR2. The buffer layer BFL may
include silicon nitride (SiNx), silicon oxide (SiOx) and silicon
oxynitride (SiOxNy), and the buffer layer BFL may be omitted
according to a material and a process condition of the base
substrate BS.
[0049] A first semiconductor layer SM1 and a second semiconductor
layer SM2 are provided on the buffer layer BFL. The first
semiconductor layer SM1 and the second semiconductor layer SM2
include a semiconductor material and serve as an active layer of
the switching TFT TR1 and the driving TFT TR2, respectively. Each
of the first and second semiconductor layers SM1 and SM2 includes a
source area SA, a drain area DA and a channel area CA provided
between the source area SA and the drain area DA. Each of the first
and second semiconductor layers SM1 and SM2 may include an
inorganic semiconductor material or an organic semiconductor
material. In an exemplary embodiment, the first and second
semiconductor layers SM1 and SM2 may include oxide semiconductor,
amorphous silicon semiconductor, crystalline silicon semiconductor
or polycrystalline silicon semiconductor. In an exemplary
embodiment, the oxide semiconductor includes oxide material having
at least one of indium (In), gallium (Ga), zinc (Zn), tin (Sn), and
any combinations thereof. In an exemplary embodiment, the first and
second semiconductor layers SM1 and SM2 may include oxide
semiconductor, such as zinc oxide ("ZnO"), tin oxide, indium oxide,
indium-zinc oxide ("IZO"), indium-tin oxide ("ITO"),
indium-gallium-zinc oxide, indium-zinc-tin oxide,
indium-gallium-zinc-tin oxide, etc. The source area SA and the
drain area DA may be doped with an n-type impurity or a p-type
impurity.
[0050] A gate insulating layer GI is disposed on the first and
second semiconductor layers SM1 and SM2.
[0051] The first gate electrode GE1 connected to the gate line GL
and the second gate electrode GE2 are disposed on the gate
insulating layer GI. The first gate electrode GE1 and the second
gate electrode GE2 are provided to cover an area corresponding to
the channel area CA of the first semiconductor layer SM1 and the
second semiconductor layer SM2, respectively.
[0052] An inter-insulating layer IL is disposed on the first and
second gate electrodes GE1 and GE2 to cover the first and second
gate electrodes GE1 and GE2. The first source electrode SE1, the
first drain electrode DE1, the second source electrode SE2, and the
second drain electrode DE2 are disposed on the inter-insulating
layer IL. The first source electrode SE1 and the first drain
electrode DE1 respectively make contact with the source area SA and
the drain area DA of the first semiconductor layer SM1 through
contact holes defined through the gate insulating layer GI and the
inter-insulating layer IL. The second source electrode SE2 and the
second drain electrode DE2 respectively make contact with the
source area SA and the drain area DA of the second semiconductor
layer SM2 through contact holes defined through the gate insulating
layer GI and the inter-insulating layer IL.
[0053] A portion of the second gate electrode GE2 and a portion of
the driving voltage line DVL respectively correspond to a first
capacitor electrode CE1 and a second capacitor electrode CE2 to
provide the capacitor Cst in cooperation with the inter-insulating
IL disposed between the portions of the second gate electrode GE2
and the driving voltage line DVL.
[0054] A passivation layer PSV is disposed on the first source
electrode SE1, the first drain electrode DE1, the second source
electrode SE2 and the second drain electrode DE2.
[0055] In an exemplary embodiment, the passivation layer PSV may
include an inorganic insulating material, e.g., silicon nitride
(SiNx), silicon oxide (SiOx), etc.
[0056] The first electrode EL1 is disposed on the passivation layer
PSV as a cathode of the organic light emitting device EL. The first
electrode EL1 is connected to the second drain electrode DE2 of the
driving TFT TR2 through a contact hole defined through the
passivation layer PSV.
[0057] One of the first electrode EL1 and the second electrode EL2
may be used as the anode and the other of the first electrode EL1
and the second electrode EL2 may be used as the cathode. Positions
and materials of the anode and the cathode may be determined
depending on a display direction. Hereinafter, the first electrode
EL1 and the second electrode EL2 will be described as the cathode
and the anode, respectively, but they should not be limited thereto
or thereby.
[0058] In an exemplary embodiment, the first electrode EL1 may
include a material having a lower work function, such as metal,
metal alloy, electric conductive compound, and a combination
thereof. In the exemplary embodiment, the first electrode EL1
includes lithium (Li), magnesium (Mg), aluminum (Al),
aluminum-lithium (Al--Li), calcium (Ca), magnesium-indium (Mg--In),
magnesium-silver (Mg--Ag), etc., for example
[0059] A pixel definition layer PDL is disposed on the base
substrate BS, on which the first electrode EL1 is disposed, to
partition the pixel area into plural areas respectively
corresponding to the pixels PXL. The pixel definition layer PDL is
protruded from the base substrate BS along the circumference of the
pixels PXL to expose an upper surface of the first electrode
EL1.
[0060] The light emitting layer EML is disposed in the pixel area
surrounded by the pixel definition layer PDL, and the second
electrode EL2 is disposed on the light emitting layer EML.
[0061] In the exemplary embodiment, the light emitting layer EML
emits the white light. The light emitting layer EML may include
various light emitting materials including a host and a dopant. In
an exemplary embodiment, as the dopant, a fluorescent dopant and a
phosphorescent dopant may be used. In an exemplary embodiment, as
the host, for example, Alq3C CBP(4,4'-N,N'-dicarbazole-biphenyl),
9,10-di(naphthalen-2-yl)anthracen(ADN), distyrylarylene ("DSA") or
any combinations thereof may be used, however, it should not be
limited thereto or thereby. According to another exemplary
embodiment, the light emitting layer EML may emit the color light,
and in this case, at least a portion of the color filters CF may be
omitted.
[0062] In an exemplary embodiment, the second electrode EL2 may
include a material having a higher work function. In a case that
the image is provided to the upward direction of the base substrate
BS, the second electrode EL2 may include a transparent conductive
layer, such as ITO, IZO, ZnO, indium tin zinc oxide ("ITZO"),
etc.
[0063] In an exemplary embodiment, an electron injection layer and
an electron transport layer may be disposed between the first
electrode EL1 and the light emitting layer EML, and a hole
injection layer and a hole transport layer may be disposed between
the light emitting layer and the second electrode EL2.
[0064] The sealing layer ENC is disposed on the color filters CF to
seal the pixels PXL and the color filters CF.
[0065] FIG. 5 is a perspective view showing the light collecting
member LCM according to an exemplary embodiment of the invention.
Hereinafter, the light collecting member LCM will be described in
detail with reference to FIGS. 1 and 5.
[0066] The light collecting member LCM is disposed on the pixels
PXL. In the illustrated exemplary embodiment (refer to FIG. 1), the
light collecting member LCM is directly disposed on the second
electrode EL2, but it should not be limited thereto or thereby.
According to exemplary embodiments, an additional layer may be
disposed between the second electrode and the light collecting
member LCM.
[0067] The light exiting from the pixels PXL transmits through the
light collecting member LCM and is collected in the upward
direction, i.e., a direction substantially vertical to an upper
surface of the base substrate BS (a forward direction to the
user).
[0068] The light collecting member LCM has a single-layer structure
or a multi-layer structure.
[0069] When the light collecting member LCM has the single-layer
structure, the light collecting member LCM is configured to include
one light collecting member LCM and provided with a protrusion
pattern protruded from one surface of the light collecting member
LCM to change the optical path of the light passing through the
light collecting member LCM. The protrusion pattern is protruded to
the upward direction or the downward direction.
[0070] When the light collecting member LCM has the multi-layer
structure, at least one layer of the light collecting member LCM
serves as the light collecting layer provided with the protrusion
pattern. That is, the light collecting member LCM includes at least
one light collecting layer. The light collecting member LCM further
includes a planarization layer disposed on the light collecting
layer to cover the protrusion pattern, and thus the upper surface
of the light collecting layer is planarized. When the light
collecting member LCM has the multi-layer structure including two
or more light collecting layers, the protrusion pattern disposed on
one of the light collecting layer may be overlapped with the
protrusion pattern disposed on the other of the light collecting
layer. In an exemplary embodiment, each light collecting layer
includes a polymer resin, e.g., polyacrylate, polycarbonate,
polyurethane, etc., for example.
[0071] In the illustrated exemplary embodiment, the light
collecting member LCM has the multi-layer structure. The light
collecting member LCM is disposed on the pixels PXL and includes a
first light collecting layer LC1 having a first protrusion pattern
PT1, a first planarization layer PZ1 disposed on the first light
collecting layer LC1, a second light collecting layer LC2 disposed
on the first collecting layer LC1 and having a second protrusion
pattern PT2, and a second planarization layer PZ2 disposed on the
second light collecting layer LC2.
[0072] The first protrusion pattern PT1 and/or the second
protrusion pattern PT2 may be, but not limited to, prism mountains.
In the exemplary embodiment, each prism mountain is extended in one
direction. In an exemplary embodiment, each prism mountain is
extended in the direction substantially in parallel to one of two
pairs of sides of the base substrate BS, extended in a direction
inclined to one side of the base substrate BS, extended in a zigzag
manner with respect to one side of the base substrate BS, or
extended along an imaginary curved line, for example.
[0073] In exemplary embodiments, each prism mountain may have
various shapes, e.g., a polygonal shape including a triangular
shape, a semi-circular shape, a semi-oval shape, etc., in a
cross-sectional view vertical to a direction in which the
protrusion pattern is extended.
[0074] The first protrusion pattern PT1 and the second protrusion
pattern PT2 have the same shape or different shapes. Ian an
exemplary embodiment, as shown in FIGS. 1 and 5, the first
protrusion pattern PT1 and the second protrusion pattern PT2 have
the triangular shape in the cross-sectional view, for example.
According to another exemplary embodiment, the first protrusion
pattern PT1 has the triangular shape in the cross-sectional view
and the second protrusion pattern PT2 has the semi-circular shape
in the cross-sectional view.
[0075] In an exemplary embodiment, the first protrusion pattern PT1
and the second protrusion pattern PT2 may be extended in different
directions. In detail, when assuming that one of the long side and
the short side of the base substrate BS is a first direction D1,
the first protrusion pattern PT1 is extended in the first direction
D1 and the second protrusion pattern PT2 is extended in a second
direction D2 crossing the first direction D1. In the illustrated
exemplary embodiment, the second direction D2 may be substantially
vertical to the first direction D1.
[0076] In the exemplary embodiment, the light collecting layer has
a refractive index different from that of the planarization layer
and the refractive index of the light collecting layer is greater
than the refractive index of the planarization layer. That is, the
first light collecting layer LC1 and the first planarization layer
PZ1 have different refractive indices from each other and the
second light collecting layer LC2 and the second planarization
layer PZ2 have different refractive indices from each other. As a
difference in the refractive index between the first light
collecting layer LC1 and the first planarization layer PZ1 becomes
large, the change in path of the light is intensified at an
interface between the first light collecting layer LC1 and the
first planarization layer PZ1. In addition, as a difference in the
refractive index between the second light collecting layer LC2 and
the second planarization layer PZ2 becomes large, the change in
path of the light is intensified at an interface between the second
light collecting layer LC2 and the second planarization layer PZ2.
The first and second light collecting layers LC1 and LC2 may
include the same material and the first and second planarization
layers PZ1 and PZ2 may include the same material.
[0077] In the illustrated exemplary embodiment, the light
collecting member LCM includes two light collecting layers, but the
number of the light collecting layers should not be limited thereto
or thereby. That is, the light collecting member LCM may include
one or three or more light collecting layers.
[0078] The light travels passing through the light collecting layer
is refracted or reflected at the interface between the protrusion
pattern and the planarization layer due to the refractive index
difference, and thus the amount of the light traveling in the
upward direction, i.e., the direction substantially vertical to the
surface of the base substrate BS, is increased. In exemplary
embodiments of the invention, the shape, extension direction and
density of the protrusion pattern may be controlled to allow the
brightness corresponding to about 50 percent (%) of a maximum
brightness of the display device exists in the angle of about -60
degrees to about 60 degrees, i.e., about 120 degrees in left and
right directions or in up and down directions, with respect to a
normal line (about 0 degree) of the surface of the base substrate
BS.
[0079] The display device having the above-mentioned structure may
be manufactured by disposing the pixels PXL on the base substrate
BS, disposing the light collecting member LCM on the pixels PXL,
disposing a color filter CF on the light collecting member LCM, and
disposing the encapsulation member ENC on the color filter CF.
[0080] Hereinafter, a method of manufacturing the display device
will be described in detail with reference to FIGS. 6A to 6G.
[0081] FIGS. 6A to 6G are cross-sectional views showing the method
of manufacturing the display device according to an exemplary
embodiment of the invention. For the convenience of explanation,
portions of the elements of the display device, e.g., the base
substrate, the pixels, etc., will be omitted, and the light
collecting member LCM will be mainly described.
[0082] Referring to FIG. 6A, the line part (not shown), the TFT
(not shown), the first electrode (not shown), the pixel definition
layer (not shown), the light emitting layer (not shown), and the
second electrode (not shown) are disposed on the base substrate.
For the convenience of explanation, the base substrate, the line
part, the TFT, the first electrode, the pixel definition layer, the
light emitting layer, and the second electrode have been shown in
the display substrate DPS.
[0083] The line part and the TFT are provided by a photolithography
process using a mask. The first electrode is provided by depositing
a conductive material on the base substrate on which the line part
and the TFT are disposed and patterning the conductive material
using a photolithography process. The pixel definition layer is
provided by disposing a photosensitive organic layer on the base
substrate on which the first electrode is disposed, patterning the
photosensitive organic layer using a mask, and curing the patterned
photosensitive organic layer. The light emitting layer is disposed
on the base substrate on which the first electrode and the pixel
definition layer are disposed. The light emitting layer is provided
on the base substrate in a fluid state and provided by removing a
solvent from the light emitting layer. The light emitting layer may
be provided on the base substrate by a printing method, e.g., an
inkjet method, a coating method using a nozzle, etc. The second
electrode is disposed on the light emitting layer.
[0084] Referring to FIG. 6A again, a first resin RS1 is coated on
the display substrate DPS. The first resin RS1 includes a
light-curable polymer resin. In the exemplary embodiment, the first
resin RS1 may be cured by an ultraviolet light UV.
[0085] A first mold MD1 having a first preliminary pattern RPT1 is
disposed on the display substrate DPS coated with the first resin
RS1. The first preliminary pattern RPT1 has a reverse shape to that
of the first protrusion pattern PT1.
[0086] Referring to FIG. 6B, the first resin RS1 is pressurized by
the first mold MD1 and the light UV is irradiated to the first
resin RS1 while the first resin RS1 is pressurized by the first
mold MD1. Thus, the first preliminary pattern RPT1 of the first
mold MD1 is transferred to the first resin RS1.
[0087] Referring to FIG. 6C, the first mold MD1 is removed, so that
the first light collecting layer LC1 is provided.
[0088] Referring to FIG. 6D, the first planarization layer PZ1 is
disposed on the first light collecting layer LC1. The first
planarization layer PZ1 includes a light-curable polymer resin and
is provided by coating a planarization material on the first light
collecting layer LC1 and irradiating the light to the planarization
material. The light-curable material of the first light collecting
layer LC1 has a refractive index different from a refractive index
of the light-curable material of the first planarization layer PZ1.
In an exemplary embodiment, the refractive index of the first light
collecting layer LC1 is greater than the refractive index of the
first planarization layer PZ1, for example.
[0089] Referring to FIG. 6E, a second resin RS2 is coated on the
display substrate DPS on which the first planarization layer PZ1 is
disposed. A second mold MD2 having a second preliminary pattern
RPT2 is disposed on the display substrate DPS coated with the
second resin RS2. The second preliminary pattern RPT2 has a reverse
shape to that of the second protrusion pattern PT2.
[0090] Referring to FIG. 6F, the second resin RS2 is pressurized by
the second mold MD2 and the light UV is irradiated to the second
resin RS2 while the second resin RS2 is pressurized by the second
mold MD2. The second resin RS2 is cured while being pressurized by
the second mold MD2, and thus the second preliminary pattern RPT2
of the second mold MD2 is transferred to the second resin RS2.
[0091] Then, the second mold MD2 is removed, and thus the second
light collecting layer LC2 is provided.
[0092] Referring to FIG. 6G, the second planarization layer PZ2 is
disposed on the second light collecting layer LC2. The second
polarization layer PZ2 includes a light-curable polymer resin and
is provided by coating a planarization material on the second light
collecting layer LC2 and irradiating the light to the planarization
material. The light-curable material of the second light collecting
layer LC2 has a refractive index different from a refractive index
of the light-curable material of the second planarization layer
PZ2. In an exemplary embodiment, the refractive index of the second
light collecting layer LC2 is greater than the refractive index of
the second planarization layer PZ2. In addition, the first light
collecting layer LC1 and the second light collecting layer LC2
include the same material, and the first planarization layer PZ1
and the second planarization layer PZ2 include the same
material.
[0093] According to another exemplary embodiment, the light
collecting member LCM may include three or more light collecting
layers and three or more planarizing layers. In this case, the
above-mentioned processes are repeatedly performed.
[0094] Then, although not shown in figures, the color filter CF is
disposed on the light emitting member LCM. The color filter CF is
provided by using a photolithography process.
[0095] The encapsulation member ENC is disposed on the color
filter. The encapsulation member ENC includes an organic insulating
material and/or an inorganic insulating material. The encapsulation
member ENC may be provided by various methods, e.g., deposition,
coating, adhesion, etc.
[0096] In the display device having the above-mentioned structure,
the light exiting from the light emitting layer travels to pass
through the light collecting layer, and thus the light is refracted
or reflected at the interface between the protrusion pattern and
the planarization layer due to the refractive index difference.
Therefore, the amount of the light traveling in the upward
direction, i.e., the direction substantially vertical to the
surface of the base substrate BS, is increased.
[0097] FIGS. 7A and 7B are graphs showing an intensity of light as
a function of a viewing angle of a conventional display device and
a display device according to an exemplary embodiment of the
invention, respectively. In the graphs, the direction vertical to
the surface of the base substrate is indicated as about 0 degrees,
and the direction substantially in parallel to the surface of the
base substrate is indicated as about 90 degrees. In the display
devices shown in FIGS. 7A and 7B, all conditions are maintained at
the same except for the light collecting member LCM is added to the
display device according to the exemplary embodiment of the
invention.
[0098] Referring to FIGS. 7A and 7B, the intensity of the light is
increased on the upper portion of the base substrate in the
exemplary embodiment of the display device according to the
invention when compared to that of the conventional display device.
In the conventional display device, a relatively uniform light is
emitted according to the angle on the basis of the angles, but the
intensity of the light is drastically increased in the upward
direction of the base substrate in the present display device. In
particular, according to the amount of the light in the
conventional display device and the exemplary embodiment of the
display device, when the angle is about 0 degrees, a luminous
intensity of the light in the conventional display device is about
0.26 candelas and a luminous intensity of the light in the
exemplary embodiment of the display device is about 0.45
candelas.
[0099] In addition, although not shown in graphs, the brightness is
increased on the upper portion of the base substrate in the
exemplary embodiment of the display device when compared to that of
the conventional display device. The brightness of the conventional
display device is about 90 nits, but the brightness of the
exemplary embodiment of the display device is about 160 nits. That
is, the brightness of the exemplary embodiment of the display
device is improved by about 70 percent (%) compared with that of
the conventional display device.
[0100] As described above, according to the display device of the
invention, the intensity of the light and the brightness are
improved in the direction substantially vertical to the display
device. Accordingly, since the brightness of the image provided to
the user is improved, the image may be clearly provided to the user
when used outdoors in which an external light exists. In addition,
since the brightness of the image is improved, the exemplary
embodiment of the display device may provide the image with the
same brightness as that of the conventional display device using a
relatively low electric power compared to that of the conventional
display device, thereby reducing power consumption of the exemplary
embodiment of the display device. Further, when the light
collecting property in a specific direction, e.g., the direction
substantially vertical to the display device, is improved, the
image may be provided to the user at a specific location.
[0101] In addition, the light collecting member LCM is able to be
easily disposed on the display substrate through low temperature
processes, e.g., a process of coating the polymer resin, a process
of pressing the polymer resin with the mold, a process of curing
the polymer resin, etc. Therefore, a high temperature process that
exerts an influence on the pixels is omitted, and thus the light
collecting member LCM is applied to a flexible display device.
[0102] In the exemplary embodiment, the light collecting member LCM
is configured to include two light collecting layers, but the
number of the light collecting layers should not be limited to two.
According to another exemplary embodiment, the light collecting
member LCM may include one or three or more light collecting
layers. In addition, the planarization layer is disposed on the
light collecting layer, but the planarization layer may be
omitted.
[0103] In the case that the planarization layer is omitted, the
encapsulation member may be directly disposed on the light
collecting layer.
[0104] In the exemplary embodiment, the protrusion pattern has the
triangular shape in the cross-sectional view, e.g., the prism
mountain, but it should not be limited thereto or thereby. FIGS. 8A
to 8C are perspective views showing light collecting layers
according to exemplary embodiments of the invention.
[0105] Referring to FIG. 8A, the protrusion pattern disposed on the
light collecting layer may include a plurality of pyramids having a
same pyramid shape in a same density.
[0106] Referring to FIG. 8B, the protrusion pattern disposed on the
light collecting layer may include a plurality of pyramids each
having a pyramid shape. The pyramids have different sizes and are
arranged in different densities depending areas of the light
collecting layer.
[0107] Referring to FIG. 8C, the protrusion pattern disposed on the
light collecting layer may have a plurality of semi-circular shapes
extended in one direction.
[0108] Although the exemplary embodiments of the invention have
been described, it is understood that the invention should not be
limited to these exemplary embodiments but various changes and
modifications can be made by one ordinary skilled in the art within
the spirit and scope of the invention as hereinafter claimed.
* * * * *